Final answer:
A papule is a small, raised lesion less than 1cm in diameter, whereas a nodule is a larger, solid lesion that is deeper within the skin and can be more than 1cm in diameter. Nodules may also display characteristics such as asymmetry, irregular borders, varied colors, and might be firm and growing.
Step-by-step explanation:
The difference between a papule and a nodule pertains to their size and depth in the skin. A papule is a small raised area of the skin, typically less than 1 centimeter in diameter, often found in conditions such as acne. On the other hand, a nodule is a larger, solid lesion that is deeper within the skin and can be more than 1 centimeter in diameter. Conditions like nodular melanoma showcase nodules that can have additional characteristics, such as being asymmetrical, having irregular borders, having varied shades of color, being elevated, firm to the touch, growing in size, and possibly being inflamed. Nodules are also described as red at the base and pale on top, as seen in cases like inflammation of the conjunctiva.